1. Field of the Invention
This invention relates generally to an apparatus for preconditioning at least partially polarized light for input to an optical modulator, and in particular, to a retarder stack for preconditioning at least partially polarized light for input to an electro-optic, magneto-optic, acusto-optic or any other type of optical modulator.
2. Background of the Related Art
The manipulation or transformation of polarized or partially polarized light is required in order to utilize a wide variety of optical components. Especially with the onset of integrated optics and the processing of optical signals, it is often necessary to controllably and predictably manipulate the polarization of light before inputting that light into such optical devices. Examples of such optical devices include electro-optic modulators, liquid crystals, magneto-optic modulators.
Many such devices require that the input light be completely or nearly completely polarized and have a known bandwidth similar to light from lasers or light emitting diodes (LEDs). It is important, however, to be able to selectively transform portions of relatively wide bandwidth light from sources other than lasers or LEDs in order to utilize such optical devices. For example, it is desirable to be able to selectively shift a certain band of frequencies within a wide band of frequencies comprising white light.